Current Search: Cell Adhesion (x)
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- Title
- Dscam1 Regulates Synapse Formation and Function in the Giant Fiber System of Drosophila.
- Creator
- Spencer, Casey L., Murphey, Rodney, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
- Abstract/Description
-
Proper formation of synapses in the developing nervous system is critical to the expected function and behavior of an adult organism. Neurons must project neurites, in the form of axons or dendrites, to target areas to complete synaptic circuits. The biochemical tool that cells use to interact with the external environment and direct the guidance of developing neurites are guidance receptors. One such guidance receptor that is extensively studied to uncover its roles in developmental...
Show moreProper formation of synapses in the developing nervous system is critical to the expected function and behavior of an adult organism. Neurons must project neurites, in the form of axons or dendrites, to target areas to complete synaptic circuits. The biochemical tool that cells use to interact with the external environment and direct the guidance of developing neurites are guidance receptors. One such guidance receptor that is extensively studied to uncover its roles in developmental disorders and disease is DSCAM (Down-Syndrome Cell Adhesion Molecule). To better understand the role of DSCAM in humans, a fly homolog Dscam1 was extensively characterized in the giant fiber system (GFS) of Drosophila to further explore its roles in axon guidance, synapse formation, and synapse function. The UAS-Gal4 system was used to alter the protein levels of Dscam1 within the giant fiber interneurons (GFs). A UAS-RNAi construct against Dscam1 was used to knockdown translation of all possible isoforms within the GFs. A UAS-Dscam1(TM2) construct was used to overexpress a single isoform of Dscam1 that is specifically trafficked to the axons. Confocal microscopy was used to determine the morphological changes associated with dysregulated Dscam1 levels. Visualization via fluorescent markers was accomplished of both pre- and post-synaptic cells, the GFs and tergotrochanteral motorneurons (TTMns), respectively, and synapse interface was determined as colocalization of the two cells. Additionally, the functional components of the GF-TTMn synapse, both gap-junctions, and presynaptic chemical active zones were tagged via fluorescent antibodies and quantified.
Show less - Date Issued
- 2023
- PURL
- http://purl.flvc.org/fau/fd/FA00014364
- Subject Headings
- Drosophila, Cell Adhesion Molecules, Nervous System, Synapses
- Format
- Document (PDF)
- Title
- ELECTRICAL IMPEDANCE SENSING OF ERYTHROCYTES AND CYTOADHESION.
- Creator
- Liu, Jia, Du, Sarah E., Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
Electrical impedance of cells is a sensitive indicator of changes in cellular structure and biophysical characteristics. Integration of electrical impedance sensing in microfluidics can be a useful tool for characterization of blood cells for their disease state, such as sickle cell disease and malaria. The first part of this dissertation presents application of a microfluidics-based electrical impedance sensor for the study of sickle cell disease. Dynamic cell sickling-unsickling process of...
Show moreElectrical impedance of cells is a sensitive indicator of changes in cellular structure and biophysical characteristics. Integration of electrical impedance sensing in microfluidics can be a useful tool for characterization of blood cells for their disease state, such as sickle cell disease and malaria. The first part of this dissertation presents application of a microfluidics-based electrical impedance sensor for the study of sickle cell disease. Dynamic cell sickling-unsickling process of blood cells in response to cyclic hypoxia was measured. Strong correlation was found between the electrical impedance data and patients’ hematological parameters such as levels of sickle hemoglobin and fetal hemoglobin. In addition, application of electrical impedance spectroscopy in narrow microfluidic channel was used for label-free flow cytometry and non-invasive assay of single sickle cells under controlled oxygen level. We demonstrate the capability of this new technique in differentiating normal red blood cells from sickle cells, as well as sickled cells from unsickled cells, using normoxic and hypoxic conditions. The second part of this dissertation reports an application of electrical impedance sensing for the study of placental malaria. Testing conditions were optimized so that electrical impedance can be used for real time monitoring of different cellular and molecular level variations in this in vitro model of placental malaria. Impedance characteristics of cell proliferation, syncytial fusion and long-term response of BeWo cells to adhesion of infected erythrocytes were obtained and related to the immunostaining results and inflammatory cytokines measurements. Comparing to the conventional optical microscope-based methods, electrical impedance sensing technique can provide a label-free, real-time monitoring tool to study erythrocytes and cytoadhesion, and can further be extended to other disease models and cell types.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013389
- Subject Headings
- Microfluidics, Erythrocytes, Electric Impedance, Sickle cell disease, Malaria, Cell Adhesion
- Format
- Document (PDF)
- Title
- The novel function of sJAM-C in promoting cytoskeleton rearrangement and migration in mammary epithelial cells.
- Creator
- Qureshi, Anila, Charles E. Schmidt College of Medicine, Department of Biomedical Science
- Abstract/Description
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Soluble form of Junctional adhesion molecule C (sJAM-C) has been identified to cause angiogenesis as well as chemotaxis in endothelial cells. However, the role of sJAM-C in the context of cancer has not been elucidated. Our atomic force microscopy (AFM) stiffness measurements of normal mammary epithelial cells (MCF 10A) have shown a two-fold decrease in cell's stiffness in response to sJAM-C. Changes in cell stiffness are indicative of modulations in a cell's mechanical properties. Our...
Show moreSoluble form of Junctional adhesion molecule C (sJAM-C) has been identified to cause angiogenesis as well as chemotaxis in endothelial cells. However, the role of sJAM-C in the context of cancer has not been elucidated. Our atomic force microscopy (AFM) stiffness measurements of normal mammary epithelial cells (MCF 10A) have shown a two-fold decrease in cell's stiffness in response to sJAM-C. Changes in cell stiffness are indicative of modulations in a cell's mechanical properties. Our results indicated that sJAM-C increased the MCF 10A cell migration about two-fold and also promoted a three-fold increase in chemotaxis. Additionally, sJAM-C treatment resulted in considerable filamentous-actin loss and peripheral actin ring breakage. We also found activation of Rho signaling pathway to be the main mechanism behind sJAM-C mediated alterations in MCF 10A cell cytoskeleton and motility. Our data present for the first time that sJAM-C is a pro metastatic mediator for normal mammary epithelial cells.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/fcla/dt/3362046
- Subject Headings
- Tight junctions (Cell biology), Cell interaction, Cell junction, Cell adhesion, Microcirculation
- Format
- Document (PDF)
- Title
- Adhesion molecules thatregulate inflammatory cell interactions.
- Creator
- Wegner, C. D., Wallace, R. W., Harbor Branch Oceanographic Institute
- Date Issued
- 1993
- PURL
- http://purl.flvc.org/fau/fd/FA00007308
- Subject Headings
- Cell Adhesion Molecules, Cellular immunity, Inflammation--Immunological aspects
- Format
- Document (PDF)
- Title
- Effects of glycosylation on melanoma interactions with type IV collagen models.
- Creator
- Aukszi, Beatrix., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
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Tumor cells interact with basement membrane collagen at the site of extravasation through distinct cellular receptors, including the α2β1 and α3β1integrins. These receptors are known to be differentially expressed in metastatic tumors, relative to the normal cells, depending on tumor type and stage of progression. The binding sites within type IV collagen for the α2β1 andα3β1 integrins have been identified. Since both of the integinspecific sequences possess at least one glycosylated Hyl...
Show moreTumor cells interact with basement membrane collagen at the site of extravasation through distinct cellular receptors, including the α2β1 and α3β1integrins. These receptors are known to be differentially expressed in metastatic tumors, relative to the normal cells, depending on tumor type and stage of progression. The binding sites within type IV collagen for the α2β1 andα3β1 integrins have been identified. Since both of the integinspecific sequences possess at least one glycosylated Hyl residue, we questioned whether glycosylation could modulate integrin binding. Triple-helical peptides with and without Lys substituted by glycosylated Hyl for Lys543 and Lys540 from the human a1(IV)531-543 gene sequence (α3β integrin-specific) and Lys393 from the human a1(IV)382-393 gene sequence (α2β1 integrin-specific) were synthesized and utilized in the present study., Cellular response to these triple helical ligands was tested with a primary melanoma cell line, WM-115, and three highly metastatic melanoma cell lines , WM-266-4, M14#5, and SK-MEL-2. Cell adhesion and cell spreading assays yielded differing results depending on whether the ligands contained glycosylated Hyl residues or not. In general, a decrease in cellular affinity toward the ligands was observed when glycosylated Hyl was present. Differences in the levels of adhesion and spreading between cell lines representing different stages of melanoma were also observed. Neutral B-galactosidase activity was detected in all four cell lines. Enzymatic activity levels were comparable for the three metastatic cell lines, whereas distinctively higher activity was detected for cells originating from a primary lesion. This acitivity can signal the potential of tumor cells to enhance and recover their invasive abilities., The ability of each cell line to remove the galactose from the peptide ligands has been investigated, to test whether tumor cells can reestablish binding relationships between the α2β1 and α3β1 integrins and type IV collagen that are reduced by glycosylation.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/FAU/186335
- Subject Headings
- Animal cell biotechnology, Combinatorial chemistry, Integrins, Research, Methodology, Cell adhesion molecules, Physiological effect
- Format
- Document (PDF)
- Title
- A Novel Role of the Ankyrin-Binding Motif of L1-Type CAM Neuroglian in Nuclear Import and Transcriptional Regulation of Myc.
- Creator
- Kakad, Priyanka P., Godenschwege, Tanja A., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
L1-type cell adhesion molecule (L1CAM) plays an essential role in the development of nervous system and is also highly relevant for the progression of diseases such as Alzheimer’s disease, stroke and cancers, some of the leading causes of human mortality. In addition to its canonical role as a plasma membrane protein organizing the cytoskeleton, recent in vitro studies have revealed that transmembrane as well as cytosolic fragments of proteolytically cleaved vertebrate L1CAM translocate to...
Show moreL1-type cell adhesion molecule (L1CAM) plays an essential role in the development of nervous system and is also highly relevant for the progression of diseases such as Alzheimer’s disease, stroke and cancers, some of the leading causes of human mortality. In addition to its canonical role as a plasma membrane protein organizing the cytoskeleton, recent in vitro studies have revealed that transmembrane as well as cytosolic fragments of proteolytically cleaved vertebrate L1CAM translocate to the nucleus and regulate expression of genes involved in DNA post-replication repair, cell cycle control, migration and differentiation. However, little is known about the in vivo function of L1CAM in the adult nervous system. This dissertation research focuses on studying in vivo nuclear translocation and function of L1CAM. Using the Drosophila model system, we first show that the sole Drosophila L1CAM homolog, Neuroglian (Nrg), is proteolytically cleaved by Alzheimer’s associated secretases, similar to L1CAM, and is also translocated to the nucleus in the adult nervous system. Subsequently, we have shown that the deletion of highly conserved Ankyrin binding domain or FIGQY motif disrupts nuclear import. Further experiments have revealed that the nuclear translocation of Nrg is in fact regulated by the phosphorylation of the FIGQY motif. Importantly, our studies also show transgenic expression of full-length Nrg or the intracellular domain of Nrg resulted in increased myc expression, which is associated with increased sensitivity to oxidative stress and reduced life span. On the other hand, deletion of the FIGQY motif or mutations preventing its phosphorylation led to decrease in myc expression. In summary, we have identified a novel role for the highly conserved Ankyrin binding domain in nuclear translocation and transcriptional regulation of the Drosophila myc oncogene, which is of high relevance to neurodegenerative diseases and cancer associated with oxidative stress.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013076
- Subject Headings
- Cell adhesion molecules., Myc proteins., Transcription, Genetic., Transcription factors, Gene expression., Ankyrins., Translocation, Genetic.
- Format
- Document (PDF)
- Title
- Functional roles of L1-Cam/Neuroglian in the nervous system of Drosophila Melanogaster.
- Creator
- Kudumala, Sirisha, Godenschwege, Tanja A., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Neuronal cell adhesion molecules of L1 family play a critical role in proper nervous system development. Various mutations on human L1-CAM that lead to severe neurodevelopmental disorders like retardation, spasticity etc. termed under L1 syndrome. The vertebrr their roles in axon pathfinding, neurite extension and cell migration, howeverate L1CAM and its homolog in Drosophila, neuroglian (nrg) have been well studied fo, much less is known about the mechanisms by which they fine tune synaptic...
Show moreNeuronal cell adhesion molecules of L1 family play a critical role in proper nervous system development. Various mutations on human L1-CAM that lead to severe neurodevelopmental disorders like retardation, spasticity etc. termed under L1 syndrome. The vertebrr their roles in axon pathfinding, neurite extension and cell migration, howeverate L1CAM and its homolog in Drosophila, neuroglian (nrg) have been well studied fo, much less is known about the mechanisms by which they fine tune synaptic connectivity to control the development and maintenance of synaptic connections within neuronal circuits. Here we characterized the essential role of nrg in regulating synaptic structure and function in vivo in a well characterized Drosophila central synapse model neuron, the Giant Fiber (GF) system. Previous studies from our lab revealed that the phosphorylation status of the tyrosine in the Ankyrin binding FIGQY motif in the intracellular domain of Nrg iscrucial for synapse formation of the GF to Tergo-Trochanteral Motor neuron (TTMn) synapse in the GF circuit. The present work provided us with novel insights into the role of Nrg-Ank interaction in regulating Nrg function during synapse formation and maintenance. By utilizing a sophisticated Pacman based genomic rescue strategy we have shown that dynamic regulation of the Neuroglian–Ankyrin interaction is required to coordinate transsynaptic development in the GF–TTMn synapse. In contrast, the strength of Ankyrin binding directly controls the balance between synapse formation and maintenance at the NMJ. Human L1 pathological mutations affect different biological processes distinctively and thus their proper characterization in vivo is essential to understand L1CAM function. By utilizing nrg14;P[nrg180ΔFIGQY] mutants that have exclusive synaptic defects and the previously characterized nrg849 allele that affected both GF guidance and synaptic function, we were able to analyze pathological L1CAM missense mutations with respect to their effects on guidance and synapse formation in vivo. We found that the human pathological H210Q, R184Q and Y1070C, but not the E309K and L120V L1CAM mutations affect outside-in signaling via the FIGQY Ankyrin binding domain which is required for synapse formation and not for axon guidance while L1CAM homophilic binding and signaling via the ERM motif is essential for axon guidance in Drosophila.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004131, http://purl.flvc.org/fau/fd/FA00004131
- Subject Headings
- Cell adhesion molecules, Cellular signal transduction, Cognitive neuroscience, Cognitive neuroscience, Drosophila melanogaster, Molecular neurobiology
- Format
- Document (PDF)